From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id B8C96C83F1D for ; Sat, 12 Jul 2025 14:52:57 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 38FA76B00A3; Sat, 12 Jul 2025 10:52:57 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 319846B00CF; Sat, 12 Jul 2025 10:52:57 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1BA426B00D0; Sat, 12 Jul 2025 10:52:57 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 018E26B00A3 for ; Sat, 12 Jul 2025 10:52:56 -0400 (EDT) Received: from smtpin08.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 7C9901A025C for ; Sat, 12 Jul 2025 14:52:56 +0000 (UTC) X-FDA: 83655904752.08.867DDAB Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf01.hostedemail.com (Postfix) with ESMTP id 035F14000B for ; Sat, 12 Jul 2025 14:52:53 +0000 (UTC) Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=HBaLs5Jj; spf=pass (imf01.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=quarantine) header.from=redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1752331974; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=HWccxkCXxuajKrmAuU1sLkFm+tfKnJGEInwGIoGkUmU=; b=kJus1YWQhdkBQag+5X71WKxNB8qLpgNL/63F0N3984BqzPxyRQPiYoD4M8UAqITW5eFlA2 7+zzNtTMEtWBZyu2mu+6wQyCuWJciLFmdItXpTBxGb/5VxvnxkyXrBkcCSl2CjpZvO+8KV SJtoV1KZI9z5vpQJ1Os9Xf42/9XP7Eo= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1752331974; a=rsa-sha256; cv=none; b=eN2uD158Gc66D89+pfI6nnKOtll7FD3WvrtCPVQ+JtrzcbQLhEuaGA/CRDEylEpR8ZJU9U wqOnidMqjOasvwyfPrUpgpbVIA0h8M0OKokfynubcLFeMt9tCmPYUIIdvKfEkeV0fdslcK d6014/tEAqXqmpCKaaEh6LdjSEIUBk4= ARC-Authentication-Results: i=1; imf01.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=HBaLs5Jj; spf=pass (imf01.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=quarantine) header.from=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1752331973; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=HWccxkCXxuajKrmAuU1sLkFm+tfKnJGEInwGIoGkUmU=; b=HBaLs5JjeRhciZIwjRdCndYlnfei9/J5B3+mgvDsVnEpfQdLQF0LruUvtudD+PLTBExFt6 4F5A0Ze4W9gD82PxqYz9eBhUhx8aUj5Z3ZUo1CU6WrzD6aZuX3X32/fcxkSbHR6nh1FJ2U ARqGi4IOP3fNFXeepgc+mPr8rCx+ub8= Received: from mail-wm1-f70.google.com (mail-wm1-f70.google.com [209.85.128.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-258--u6fzqv3OMOWAakaDQjcVw-1; Sat, 12 Jul 2025 10:52:52 -0400 X-MC-Unique: -u6fzqv3OMOWAakaDQjcVw-1 X-Mimecast-MFC-AGG-ID: -u6fzqv3OMOWAakaDQjcVw_1752331971 Received: by mail-wm1-f70.google.com with SMTP id 5b1f17b1804b1-43e9b0fd00cso16114535e9.0 for ; Sat, 12 Jul 2025 07:52:51 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1752331971; x=1752936771; h=content-transfer-encoding:in-reply-to:organization:autocrypt :content-language:from:references:cc:to:subject:user-agent :mime-version:date:message-id:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to; bh=HWccxkCXxuajKrmAuU1sLkFm+tfKnJGEInwGIoGkUmU=; b=uJTFhJPCBShhDZGRhspN3QCLuw7PNS0CtxU2O+I0zcmRuOeiqSqQOKEWP5Xa37KCLq bpQLSrxr4L9bVPg/1aEYtbTI+0VzZj4XTDl3vznb2ZprzihTB8eu2bLO34sX+SmT6JTr EimpHiZnA51Io0i4aHWV+QNmjThJ19XjIYiIqCYNcBOyDyQKRRgTsfggWC7+M8JmaDPm bvqI9fDOEFfjEQnnFYRLbJNkL8p1J5hsfQ2wNVl+U35ngVafzdubUu7998M9SrOzQSyT oA495zvqAP75rbJTdh6REERsYPRx4/ES75+tzXVLKfFzNaZVwlZq02AFsPvNHdE7lkKl CFRA== X-Forwarded-Encrypted: i=1; AJvYcCXdlvfFLV0VPQLLHuc5dk6c2d9pXI8tiwGw+VKJD4Uj0FxqkNOhSDngGqUUpa9N+NsXZuuluiWBMw==@kvack.org X-Gm-Message-State: AOJu0Yzd1bVjjvzUzh5AxlDj/NVw0Cwmd4LjdXVvaN0C85aJTGA7+rCr MyGqwYvHY3oMO2UnIshDMsdJ6jF90y0Bp/gdQk9OdjlnVKWfphyhVFzqSmH+2+7Z7PvcLjxAxZK 6PuSCN+I+ML4k19/hScYrAy1meJiwks9mgYiE7HlkW7flzCdm79Co X-Gm-Gg: ASbGncuGUKDQtx7QWuNqex+VoK0Q+HNvNejHc1xBAdKwYNgXgxKDdgLSp8Ef6ZrfnIq TeAsH0BE+OwdSYQrFP0tBoeK9DFHhfcd69l3gfX6bYylMJRo/Plve2PNbJTL798Gnryv36DxPQ+ wOPnh8hc5ZEXWsZFMPthpB+HOn8e1872EXSs9CJUZzHu8J+Eco6hbfZGF9Hja4dLyy2gI8ykhrv M8a8mvFYONK0f3Za4NOuPIlEXuWhsek5LDrDThCPSK+g1b+T5BGMeuMuxSVxGkVDbnRO9wf/BOh //srMKQO5XaQo9f7GgEt8J6OlZV6umXBASLk/4YpxMa5qX/96SNkOp5iTQyJLamQyOhwooP6QAp Wny++/mBKORfV8inV25tozAZQx0DVhAV2waD6SndqZSLDQYV8tswNGDJDYLfcaZ1bedY= X-Received: by 2002:a05:600c:3e83:b0:453:92e:a459 with SMTP id 5b1f17b1804b1-454db8d8d06mr112045035e9.16.1752331970664; Sat, 12 Jul 2025 07:52:50 -0700 (PDT) X-Google-Smtp-Source: AGHT+IHI0Jdvn0mZ+OKJIfLwFbj8UH/AqPLNeecxxGrUnR0H54nG4V7l4C2eBcDE8jXu8TJAJaFkMw== X-Received: by 2002:a05:600c:3e83:b0:453:92e:a459 with SMTP id 5b1f17b1804b1-454db8d8d06mr112044665e9.16.1752331970078; Sat, 12 Jul 2025 07:52:50 -0700 (PDT) Received: from ?IPV6:2003:d8:2f23:f800:2113:1f36:a0b7:668a? (p200300d82f23f80021131f36a0b7668a.dip0.t-ipconnect.de. [2003:d8:2f23:f800:2113:1f36:a0b7:668a]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4560dda2263sm8517455e9.1.2025.07.12.07.52.47 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 12 Jul 2025 07:52:49 -0700 (PDT) Message-ID: <3acd967e-30b3-4e76-9e1b-41c1e19d4f31@redhat.com> Date: Sat, 12 Jul 2025 16:52:46 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net-next v9 3/8] page_pool: access ->pp_magic through struct netmem_desc in page_pool_page_is_pp() To: Pavel Begunkov , Byungchul Park , Mina Almasry , "willy@infradead.org" Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, kernel_team@skhynix.com, kuba@kernel.org, ilias.apalodimas@linaro.org, harry.yoo@oracle.com, hawk@kernel.org, akpm@linux-foundation.org, davem@davemloft.net, john.fastabend@gmail.com, andrew+netdev@lunn.ch, toke@redhat.com, tariqt@nvidia.com, edumazet@google.com, pabeni@redhat.com, saeedm@nvidia.com, leon@kernel.org, ast@kernel.org, daniel@iogearbox.net, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, horms@kernel.org, linux-rdma@vger.kernel.org, bpf@vger.kernel.org, vishal.moola@gmail.com, hannes@cmpxchg.org, ziy@nvidia.com, jackmanb@google.com References: <20250710082807.27402-1-byungchul@sk.com> <20250710082807.27402-4-byungchul@sk.com> <20250711011435.GC40145@system.software.com> <582f41c0-2742-4400-9c81-0d46bf4e8314@gmail.com> From: David Hildenbrand Autocrypt: addr=david@redhat.com; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZgEEwEIAEICGwMGCwkIBwMCBhUIAgkKCwQW AgMBAh4BAheAAhkBFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl8Ox4kFCRKpKXgACgkQTd4Q 9wD/g1oHcA//a6Tj7SBNjFNM1iNhWUo1lxAja0lpSodSnB2g4FCZ4R61SBR4l/psBL73xktp rDHrx4aSpwkRP6Epu6mLvhlfjmkRG4OynJ5HG1gfv7RJJfnUdUM1z5kdS8JBrOhMJS2c/gPf wv1TGRq2XdMPnfY2o0CxRqpcLkx4vBODvJGl2mQyJF/gPepdDfcT8/PY9BJ7FL6Hrq1gnAo4 3Iv9qV0JiT2wmZciNyYQhmA1V6dyTRiQ4YAc31zOo2IM+xisPzeSHgw3ONY/XhYvfZ9r7W1l pNQdc2G+o4Di9NPFHQQhDw3YTRR1opJaTlRDzxYxzU6ZnUUBghxt9cwUWTpfCktkMZiPSDGd KgQBjnweV2jw9UOTxjb4LXqDjmSNkjDdQUOU69jGMUXgihvo4zhYcMX8F5gWdRtMR7DzW/YE BgVcyxNkMIXoY1aYj6npHYiNQesQlqjU6azjbH70/SXKM5tNRplgW8TNprMDuntdvV9wNkFs 9TyM02V5aWxFfI42+aivc4KEw69SE9KXwC7FSf5wXzuTot97N9Phj/Z3+jx443jo2NR34XgF 89cct7wJMjOF7bBefo0fPPZQuIma0Zym71cP61OP/i11ahNye6HGKfxGCOcs5wW9kRQEk8P9 M/k2wt3mt/fCQnuP/mWutNPt95w9wSsUyATLmtNrwccz63XOwU0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAHCwXwEGAEIACYCGwwWIQQb2cqtc1xMOkYN/MpN3hD3 AP+DWgUCXw7HsgUJEqkpoQAKCRBN3hD3AP+DWrrpD/4qS3dyVRxDcDHIlmguXjC1Q5tZTwNB boaBTPHSy/Nksu0eY7x6HfQJ3xajVH32Ms6t1trDQmPx2iP5+7iDsb7OKAb5eOS8h+BEBDeq 3ecsQDv0fFJOA9ag5O3LLNk+3x3q7e0uo06XMaY7UHS341ozXUUI7wC7iKfoUTv03iO9El5f XpNMx/YrIMduZ2+nd9Di7o5+KIwlb2mAB9sTNHdMrXesX8eBL6T9b+MZJk+mZuPxKNVfEQMQ a5SxUEADIPQTPNvBewdeI80yeOCrN+Zzwy/Mrx9EPeu59Y5vSJOx/z6OUImD/GhX7Xvkt3kq Er5KTrJz3++B6SH9pum9PuoE/k+nntJkNMmQpR4MCBaV/J9gIOPGodDKnjdng+mXliF3Ptu6 3oxc2RCyGzTlxyMwuc2U5Q7KtUNTdDe8T0uE+9b8BLMVQDDfJjqY0VVqSUwImzTDLX9S4g/8 kC4HRcclk8hpyhY2jKGluZO0awwTIMgVEzmTyBphDg/Gx7dZU1Xf8HFuE+UZ5UDHDTnwgv7E th6RC9+WrhDNspZ9fJjKWRbveQgUFCpe1sa77LAw+XFrKmBHXp9ZVIe90RMe2tRL06BGiRZr jPrnvUsUUsjRoRNJjKKA/REq+sAnhkNPPZ/NNMjaZ5b8Tovi8C0tmxiCHaQYqj7G2rgnT0kt WNyWQQ== Organization: Red Hat In-Reply-To: <582f41c0-2742-4400-9c81-0d46bf4e8314@gmail.com> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: 8VKU2iFgbh2He0l7Gj0_zx96jnqx_E7H9-rzMF7ZaiY_1752331971 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 035F14000B X-Stat-Signature: zyseef47pd6oc4erhj6riwwwnrjusnbr X-Rspam-User: X-HE-Tag: 1752331973-898799 X-HE-Meta: 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 2IrjPATp 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 12.07.25 15:58, Pavel Begunkov wrote: > On 7/11/25 02:14, Byungchul Park wrote: > ...>>> +#ifdef CONFIG_PAGE_POOL >>>> +/* XXX: This would better be moved to mm, once mm gets its way to >>>> + * identify the type of page for page pool. >>>> + */ >>>> +static inline bool page_pool_page_is_pp(struct page *page) >>>> +{ >>>> + struct netmem_desc *desc = page_to_nmdesc(page); >>>> + >>>> + return (desc->pp_magic & PP_MAGIC_MASK) == PP_SIGNATURE; >>>> +} >>> >>> pages can be pp pages (where they have pp fields inside of them) or >>> non-pp pages (where they don't have pp fields inside them, because >>> they were never allocated from the page_pool). >>> >>> Casting a page to a netmem_desc, and then checking if the page was a >>> pp page doesn't makes sense to me on a fundamental level. The >>> netmem_desc is only valid if the page was a pp page in the first >>> place. Maybe page_to_nmdesc should reject the cast if the page is not >>> a pp page or something. >> >> Right, as you already know, the current mainline code already has the >> same problem but we've been using the werid way so far, in other words, >> mm code is checking if it's a pp page or not by using ->pp_magic, but >> it's ->lur, ->buddy_list, or ->pcp_list if it's not a pp page. >> >> Both the mainline code and this patch can make sense *only if* it's >> actually a pp page. It's unevitable until mm provides a way to identify >> the type of page for page pool. Thoughts? > Question to mm folks, can we add a new PGTY for page pool and use > that to filter page pool originated pages? Like in the incomplete > and untested diff below? https://lore.kernel.org/all/77c6a6dd-0e03-4b81-a9c7-eaecaa4ebc0b@redhat.com/ We then want to do (on top of mm/mm-unstable) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index fa09154a799c6..cb90d6a3fd9d9 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1042,7 +1042,6 @@ static inline bool page_expected_state(struct page *page, #ifdef CONFIG_MEMCG page->memcg_data | #endif - page_pool_page_is_pp(page) | (page->flags & check_flags))) return false; @@ -1069,8 +1068,6 @@ static const char *page_bad_reason(struct page *page, unsigned long flags) if (unlikely(page->memcg_data)) bad_reason = "page still charged to cgroup"; #endif - if (unlikely(page_pool_page_is_pp(page))) - bad_reason = "page_pool leak"; return bad_reason; } @@ -1379,9 +1376,11 @@ __always_inline bool free_pages_prepare(struct page *page, mod_mthp_stat(order, MTHP_STAT_NR_ANON, -1); folio->mapping = NULL; } - if (unlikely(page_has_type(page))) + if (unlikely(page_has_type(page))) { + WARN_ON_ONCE(PageNetpp(page)); /* Reset the page_type (which overlays _mapcount) */ page->page_type = UINT_MAX; + } if (is_check_pages_enabled()) { if (free_page_is_bad(page)) > > > commit 8fc2347fb3ff4a3fc7929c70a5a21e1128935d4a > Author: Pavel Begunkov > Date: Sat Jul 12 14:29:52 2025 +0100 > > net/mm: use PGTY for tracking page pool pages > > Currently, we use page->pp_magic to determine whether a page belongs to > a page pool. It's not ideal as the field is aliased with other page > types, and thus needs to to rely on elaborated rules to work. Add a new > page type for page pool. > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 0ef2ba0c667a..975a013f1f17 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -4175,7 +4175,7 @@ int arch_lock_shadow_stack_status(struct task_struct *t, unsigned long status); > #ifdef CONFIG_PAGE_POOL > static inline bool page_pool_page_is_pp(struct page *page) > { > - return (page->pp_magic & PP_MAGIC_MASK) == PP_SIGNATURE; > + return PageNetpp(page); > } > #else > static inline bool page_pool_page_is_pp(struct page *page) > diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h > index 4fe5ee67535b..9bd1dfded2fc 100644 > --- a/include/linux/page-flags.h > +++ b/include/linux/page-flags.h > @@ -957,6 +957,7 @@ enum pagetype { > PGTY_zsmalloc = 0xf6, > PGTY_unaccepted = 0xf7, > PGTY_large_kmalloc = 0xf8, > + PGTY_netpp = 0xf9, > > PGTY_mapcount_underflow = 0xff > }; > @@ -1101,6 +1102,11 @@ PAGE_TYPE_OPS(Zsmalloc, zsmalloc, zsmalloc) > PAGE_TYPE_OPS(Unaccepted, unaccepted, unaccepted) > FOLIO_TYPE_OPS(large_kmalloc, large_kmalloc) > > +/* > + * Marks page_pool allocated pages > + */ > +PAGE_TYPE_OPS(Netpp, netpp, netpp) > + > /** > * PageHuge - Determine if the page belongs to hugetlbfs > * @page: The page to test. > diff --git a/include/net/netmem.h b/include/net/netmem.h > index de1d95f04076..20f5dbb08149 100644 > --- a/include/net/netmem.h > +++ b/include/net/netmem.h > @@ -113,6 +113,8 @@ static inline bool netmem_is_net_iov(const netmem_ref netmem) > */ > static inline struct page *__netmem_to_page(netmem_ref netmem) > { > + DEBUG_NET_WARN_ON_ONCE(netmem_is_net_iov(netmem)); > + > return (__force struct page *)netmem; > } > > diff --git a/net/core/netmem_priv.h b/net/core/netmem_priv.h > index cd95394399b4..e38c64da1a78 100644 > --- a/net/core/netmem_priv.h > +++ b/net/core/netmem_priv.h > @@ -13,16 +13,11 @@ static inline void netmem_or_pp_magic(netmem_ref netmem, unsigned long pp_magic) > __netmem_clear_lsb(netmem)->pp_magic |= pp_magic; > } > > -static inline void netmem_clear_pp_magic(netmem_ref netmem) > -{ > - WARN_ON_ONCE(__netmem_clear_lsb(netmem)->pp_magic & PP_DMA_INDEX_MASK); > - > - __netmem_clear_lsb(netmem)->pp_magic = 0; > -} > - > static inline bool netmem_is_pp(netmem_ref netmem) > { > - return (netmem_get_pp_magic(netmem) & PP_MAGIC_MASK) == PP_SIGNATURE; > + if (netmem_is_net_iov(netmem)) > + return true; > + return page_pool_page_is_pp(netmem_to_page(netmem)); > } > > static inline void netmem_set_pp(netmem_ref netmem, struct page_pool *pool) > diff --git a/net/core/page_pool.c b/net/core/page_pool.c > index 05e2e22a8f7c..52120e2912a6 100644 > --- a/net/core/page_pool.c > +++ b/net/core/page_pool.c > @@ -371,6 +371,13 @@ struct page_pool *page_pool_create(const struct page_pool_params *params) > } > EXPORT_SYMBOL(page_pool_create); > > +static void page_pool_set_page_pp_info(struct page_pool *pool, > + struct page *page) > +{ > + __SetPageNetpp(page); > + page_pool_set_pp_info(page_to_netmem(page)); > +} > + > static void page_pool_return_netmem(struct page_pool *pool, netmem_ref netmem); > > static noinline netmem_ref page_pool_refill_alloc_cache(struct page_pool *pool) > @@ -534,7 +541,7 @@ static struct page *__page_pool_alloc_page_order(struct page_pool *pool, > } > > alloc_stat_inc(pool, slow_high_order); > - page_pool_set_pp_info(pool, page_to_netmem(page)); > + page_pool_set_page_pp_info(pool, page); > > /* Track how many pages are held 'in-flight' */ > pool->pages_state_hold_cnt++; > @@ -579,7 +586,7 @@ static noinline netmem_ref __page_pool_alloc_netmems_slow(struct page_pool *pool > continue; > } > > - page_pool_set_pp_info(pool, netmem); > + page_pool_set_page_pp_info(pool, __netmem_to_page(netmem)); > pool->alloc.cache[pool->alloc.count++] = netmem; > /* Track how many pages are held 'in-flight' */ > pool->pages_state_hold_cnt++; > @@ -654,7 +661,6 @@ s32 page_pool_inflight(const struct page_pool *pool, bool strict) > void page_pool_set_pp_info(struct page_pool *pool, netmem_ref netmem) > { > netmem_set_pp(netmem, pool); > - netmem_or_pp_magic(netmem, PP_SIGNATURE); > > /* Ensuring all pages have been split into one fragment initially: > * page_pool_set_pp_info() is only called once for every page when it > @@ -669,7 +675,6 @@ void page_pool_set_pp_info(struct page_pool *pool, netmem_ref netmem) > > void page_pool_clear_pp_info(netmem_ref netmem) > { > - netmem_clear_pp_magic(netmem); > netmem_set_pp(netmem, NULL); > } > > @@ -730,8 +735,11 @@ static void page_pool_return_netmem(struct page_pool *pool, netmem_ref netmem) > trace_page_pool_state_release(pool, netmem, count); > > if (put) { > + struct page *page = netmem_to_page(netmem); > + > page_pool_clear_pp_info(netmem); > - put_page(netmem_to_page(netmem)); > + __ClearPageNetpp(page); > + put_page(page); > } > /* An optimization would be to call __free_pages(page, pool->p.order) > * knowing page is not part of page-cache (thus avoiding a > -- Cheers, David / dhildenb